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Design system

The tokens and components XYZ is built from, shown in the current theme.

Colour

Surfaces and text

canvas
surface
sunken
ink
ink-muted
rule
border-strong
focus

Skill areas

Programming

cat-programming
cat-programming-fill
cat-programming-soft

Logic & Critical Thinking

cat-logic
cat-logic-fill
cat-logic-soft

Language & Communication

cat-language
cat-language-fill
cat-language-soft

Feedback

correct
correct-soft
partial
partial-soft
incorrect
incorrect-soft

Typography

Practice turns into skill

Practice turns into skill

Practice turns into skill

Get better at practical skills by solving short challenges, understanding every mistake and seeing which skills grow stronger. XYZ starts with JavaScript, logic and English.

Feedback explains why an answer is right or wrong, and names the specific mistake when it is a common one.

const items = [0, 1, 2];
console.log(items.length === 3); // O0 l1 I

Components

Buttons

Badges

ProgrammingLogic & Critical ThinkingLanguage & CommunicationMathematicsDesign & Digital SkillsPlannedDraftBeginner

Notices

Your progress is saved in this browser.

Correct

Read code and say what it prints.

Partly correct

Complete code or a sentence.

Not quite

Arrange steps, events or words.

Challenge cards

Rendered from the draft fixtures in content/. They validate the content model and are not playable or listed.

  • ProgrammingPredict the outputDraft

    What push returns

    Predict what push gives back and what it does to the array.

    Beginner2 minArrays
  • ProgrammingWrite codeDraft

    Clamp a number

    Write a function that keeps a value inside a range.

    Beginner6 minFunctions, Control flow
  • ProgrammingMultiple choiceDraft

    Two counters

    Decide whether two closures share their state.

    Intermediate3 minClosures, Functions
  • ProgrammingFill in the blankDraft

    Keep the even numbers

    Complete a one-line array method call.

    Beginner2 minArrays, Functions
  • ProgrammingDebugDraft

    The total is too small

    Find why a loop leaves a number out.

    Beginner5 minDebugging, Control flow
  • Logic & Critical ThinkingPut in orderDraft

    Finishing order

    Work out a race result from three clues.

    Beginner3 minDeduction
  • Logic & Critical ThinkingNumeric answerDraft

    Growing gaps

    Find the next number in a sequence.

    Beginner2 minSequences and patterns
  • Logic & Critical ThinkingMultiple choiceDraft

    If it rains

    Decide what follows from a conditional and a fact.

    Intermediate2 minConditional reasoning, Evaluating arguments
  • Language & CommunicationMultiple choiceDraft

    Where does always go?

    Place adverbs of frequency correctly.

    Intermediate2 minWord order
  • Language & CommunicationFill in the blankDraft

    Every day

    Use the present simple with he, she and it.

    Beginner1 minVerb tenses